Apparently upset about the price of a pair of shades in a Chelsea boutique, a man yesterday brandished a knife and stabbed the store manager. He stabbed more people outside before being subdued by a Salsa DJ and his crew.

The unidentified slasher, who police say is a black man in his 20's, entered Solstice Sunglasses on Ninth Avenue yesterday afternoon, asked about the price of a pair of sunglasses and then stabbed the store manager in the stomach. "He was mumbling. He wasn't all there," one store employee told the Daily News. He then went outside, smashed the window of a nearby diner with a table, and then turned his attention to an outdoor Salsa dancing class in a traffic triangle:

He stabbed one of the dancers, believed to be a 28-year-old man, in the arm, and then knocked over a DJ's musical equipment.

"He pushed the equipment over and he pulled out a knife and started swinging it," said the DJ's bouncer, Rafael Negron, 48, of Washington Heights.

"I picked up a chair. ... He was going to stab other people. We used enough force to stop him. His eyes were popping out."

Another witness, James Ortiz told the Post, "The guy was crazy, he looked like he had rabies or something." Four people were stabbed by the man before he was arrested and carted off in a straight jacket.